Gaps of immunization against measles shown by a sero-surveys conducted from residual hospital samples in Vietnam (4 hospitals represented by red triangles). Estimates of sero-prevalence are shown from 3 age classes (0-1 yr, 1-2 yr and 2-3 yr) for girls and boys and can be compared to estimates inferred from vaccination cards (through the UNICEF/MICS surveys) in each of 6 regions in Vietnam. The minimum level of sero-prevalence to protect a population is 95%.
